Epidiascopic and diascopic projecting apparatus



A. MOTTU Nov. 23, 1954 EPIDIASCOPIC AND DIASCOPIC PROJECTJ TNG APPARATUS 2 Sheets-Sheet 1 Filed March 51, 1953 A. MOTTU Nov. 23, 1954 EPIDIASCOPIC AND DIASCOPIC PROJECTING APPARATUS Filed March 31, 1953 2 Sheets-Sheet 2 nited States Patent EPIDIASCOPIC AND DIASCOPIC PROJ ECTING APPARATUS Andre Mottu, Geneva, Switzerland, assignor to 'Societe Geaevoise dilnstruments de Physique, Geneva,Switzeriand, a firm of Switzerland Appiication'lliareh -31, 1953, Serial No. 345,841 Claims priority, application Switzerland April"4,'1952 3 Claims. (miss- &4)

Most outline projectors producing diascopic projections of the outline and episcopic projections of the actual surface to be examined include a luminous source constituted by two separate lanterns adapted for use respectively for diascopic and episcopic purposes.

Whenit is desired to obtain simultaneously a combined epidiascopic .projectionjthe t-wo lanterns have'to be illuminated simultaneously. Other projectors include only one lantern which provides for only or'ietype of illumination while the other type'is'obtained'b'y deflecting the luminous beam produced by said lantern by means of a system constituted by a plurality of mirrors, which arrangement prevents obtaining simultaneously the episcopic and diascopic projections.

The object of my present invention is to allow, while resorting only to a single source of light, the execution, by means of a single apparatus, selectively'of a combined epidiascopic projection and of episcopic or diascopic projections separately.

According to my invention, this outline projecting apparatus comprises a single luminous source and a mirror positioned with reference to the source of light beyond the object plane i. e. the plane in which is located the workpiece surface to be checked, said mirror returning into the objective the luminous rays alongside of the workpiece illuminated episcopically so as to produce at the same time a diascopic illumination of said workpiece.

Accompanying drawings illustrate by way of example a preferred embodiment of the object of my invention.

In said drawings:

Fig. 1 is a transverse cross-section through line I-I of Fig. 2 of the front part of the apparatus in the position providing a diascopic illumination.

Fig. 2 is a longitudinal cross-section of the same aps,

paratus through line II--II of Fig. 1.

Figs. 3, 4 and 5 illustrate diagrammatically the paths followed by the luminous beam for diascopic, episcopic and epidiascopic illumination respectively.

The apparatus illustrated includes a frame 14 carrying a movable arm 2 that is pivotally secured thereto at 15 (Fig. 2) and adapted to occupy two extreme positions designated respectively by A and B in Figs. 1 and 2. Said movable arm 2 carries a lantern 1 enclosing a bulb 3 together with a condenser 4 to the front of which may be secured an auxiliary removable condenser 5.

The workpiece to be examined, shown at 7, is laid over a transparent table or slide 16 carried by a support 17 of adjustable height. This support is mounted slidingly on the upright 18 forming part of the frame of the apparatus. The latter includes also an auxiliary mirror 6 pivotally secured at 19 to the frame and adapted to occupy selectively two separate positions appearing respectively in solid lines and in dot-and-dash lines in Fig. 1. An objective 3 projects the luminous rays through the agency of the two stationary mirrors 12 and 13 onto the screen 9 (Fig. 2). Lastly, the apparatus includes a preferably stationary condenser 10 located in register with the bulb 3 when the lantern occupies its lowermost position B and a corresponding semi-transparent blade "11 carried by a pin 20 secured to the casing 14; this blade 11 is arranged at with reference to the optic axis of the condenser.

The apparatus operates as follows:

To obtain an epidiascopic illumination, the lantern 1 is set in its lower position B as shown in dot-anddash lines in Figs. 1 and 2; the condenser 5 is removed and the auxiliary mirror 6 is laid in a horizontal .position perpendicularly to the optic axis of the apparatus coinciding with the axis of the objective 4. The bulb 3 sends through the condenser 4 and the stationary condenser 19 a parallel beam of which'a'fraction-is deflected at by the semi-transparent blade 11 so as to pass through the objective 8 and to illuminate the workpiece to be checked 7. The'light reflected by the workpiece is collected by the objective 8 and returns through the blade'll so as to'form on the screen 9 an episcopicimage of the surface of the workpiece after reflection by-the mirrors 12 and-13 (Fig. 5). '-A part of the rays serving for this episcopic illumination passes to the side of' the workpiece 7 and through thepossible openings in the latter without being reflected and this unrefiected light reaches the mirror 6 which throws it backonto the workpiece 7 as if said light were-produced by a virtual source of light located'above said workpiece which cuts off these reflected rays ;so as to produce a diascopically illuminating beam. The objective 8 collects the diascopic illumination of -the outline of the workpiece and projects it also onto the-screen 9 so that thenimage of the outline is superposed exactly over the episcopic image. This produces consequent ly the desired epidiascopic illumination by means of a single source of light as shown in Fig. 5.

The apparatus described allows also obtaining episcopic illumination alone and for this purpose the lantern still occupies the same lower position B as disclosed while the auxiliary mirror 6 is raised into a collapsed position, inclined at 45 with reference to horizontality as shown in solid lines in Fig. 1. It cannot therefore throw back as precedingly onto the workpiece 7 a part of the episcopic illuminating rays and consequently the diascopic illumination is cut out. This corresponds to the sketch in Fig. 4.

Lastly, the apparatus described allows also producing only a diascopic illumination; to this end, the lantern 1 carried by the movable arm 2 is set in the upper position A as shown in solid lines in Figs. 1 and 2, and the removable condenser 5 is reinserted on the lantern. The luminous rays produced by the bulb 3 pass through the condenser 4 and through the removable condenser 5 so as to produce a parallel beam which is then deflected at 90 by the auxiliary mirror 6 extending at 45 with reference to horizontality. The luminous beam thus reflected reaches the workpiece to be checked 7 which cuts it oif partly so that the diascopic outline of said workpiece is projected by the objective 8 as precedingly onto the screen 9 as shown diagrammatically in Fig. 3.

In order to increase the luminosity of the image on the screen, the reflecting surface of the mirror 6 may have a concave shape.

What I claim is:

1. An epidiascopic projector comprising a casing, a screen therein, a lever pivotally secured to the frame and adapted to assume two extreme positions, a lautern carried by said lever, a transparent workpiece-carrying table, means for adjusting its position along an optic axis extending perpendicularly to the table and in the plane of the optic axes of the lantern in its extreme positions, an objective located to one side of the table, a semi-transparent plate located behind the objective with reference to the table in register with one of the extreme positions of the lantern, means for projecting the image of the workpiece on the table, formed by the projector beam passing through the objective and semi-transparent plate onto the screen, a mirror facing the side of the table opposed to the objective and registering with the second position of the lantern and adapted to assume selectively a position parallel with the table for returning the luminous rays from the lantern in the first position onto said workpiece and an oblique position at 45 with reference to the table for which it throws back the light of the lantern in its second position onto the transparent table.

2. An epidiascopic projector comprising a casing, a screen therein, a lever pivotally secured to the frame and adapted to assume two extreme positions, a lantern carried by said lever and including a bulb and a condenser, two further condensers mounted on the easing in register with the two positions of the lantern condenser, one at least of the two auxiliary condensers being removably fitted in said casing, a transparent workpiece-carrying table, means for adjusting its position along an optic axis extending perpendicularly to the table and in the plane of the optic axes of the lantern in its extreme positions, an objective located to one side of the table, a semi-transparent plate located behind the objective with reference to the table in register with one of the extreme positions of the lantern, means for projecting the image of the workpiece on the table, formed by the projector beam passing through the objective and the semi-transparent plate onto the screen, a mirror facing the side of the table opposed to the objective and registering with the second position of the lantern and adapted to assume selectively a position parallel with the table for returning the luminous rays from the lantern in the first position onto said workpiece and an oblique position at 45 with reference to the table for which it throws back the light of the lantern in its second position onto the transparent table.

3. An epidiascopic projector comprising a casing, a

screen therein, a lantern carried selectively by the casing in two different positions, a transparent workpiececarrying table, means for adjusting its position along an optic axis extending perpendicularly to the table and in the plane of the optic axes of the lantern in its extreme positions, an objective located to one side of the table, a semi-transparent plate located behind the objective with reference to the table in register with one of the extreme positions of the lantern, means for projecting the image of the workpiece on the table formed by the projector beam passing through the objective and the semi-transparent plate onto the screen, a mirror facing the side of the table opposed to the objective and registering with the second position of the lantern and adapted to assume selectively a position parallel with the table for returning the luminous rays from the lantern in the first position onto said workpiece and an oblique position at 45 with reference to the table for which it throws back the light of the lantern in its second position onto the transparent table and shifts away from the objective the luminous rays projected by the lantern in the first position onto the workpiece and that are not arrested by the workpiece.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,098,311 Schattschneider Nov. 9, 1937 2,317,282 LopeZ-Henriques Apr. 20, 1943 2,373,928 Turrettini Apr. 17, 1945 2,373,929 Turrettini Apr. 17, 1945 2,373,930 Turrettini Apr. 17, 1945 2,414,977, Reid et a1. Jan. 28, 1947 

